Chair

ABSTRACT

In order to improve operationality to produce functions, to prevent an assembling or disassembling procedure from being complicated and to simplify a structure of a chair of multi-function, a chair having a plurality of operating portions to adjust a height of a back or a seat or to adjust a rocking motion mechanically is so arranged that each of more than two operating portions as some or all of the operating portions is made to rotate around a predetermined shaft respectively, each shaft of the operating portions is arranged in a line, and more than two operating portions as some or all of the operating portions are arranged in a line and the chair comprises an operation receiving portion as a mechanism to work each mechanism directly and a link means that connects the operating portion and the operation receiving portion, some or all of the adjusting portions that are arranged in the link means in order to adjust a motion range of the operation receiving portion that works with operation of the operating portion are gathered in a predetermined area.

FIELD OF THE ART

[0001] This invention relates to a chair that has a plurality of operating portions for adjusting a height of a back or a seat or for adjusting a rocking motion.

BACKGROUND ART

[0002] Chairs have recently been multi-functionalized to improve comfortability in sitting or usability. Typically there are, for example, a mechanism to adjust a height of a back or a seat, a mechanism to switch the seat from a rocking state to a fixed state and a mechanism to slide the seat back and forth. An operating portion is provided for each mechanism and conventionally these operating portions are arranged dispersedly at a plurality of positions on the chair.

[0003] However, as a first problem, a user of the chair might be unsatisfied with usability because it is difficult for the user to recognize a position of the operating portion if the operating portions are arranged dispersedly. In addition, in case that a chair is additionally multi-functionalized in the future, if the operating portions are arranged dispersedly, chances are high that operationality would be impaired due to weight of numbers of the operating portions.

[0004] In order to solve the above problem, the present claimed invention intends to improve operationality for a chair having a plurality of operating portions to adjust a height of a back or a seat or to adjust a rocking motion, especially for a multi-functionalized chair by gathering some or all of the operating portions.

[0005] Meanwhile since each mechanism is provided under the seat or a backside of a back, an operating portion to activate the mechanism is arranged at a position accessible for a user and the operating portion is linked with an operation receiving portion through a link means such as a link wire. Due to this arrangement, an adjusting portion is provided in order to coincide an operation range of the operating portion with a motion range to activate the mechanism of the operation receiving portion. The adjusting portion is conventionally arranged dispersedly near the operation receiving portion.

[0006] However, as a second problem if pluralities of adjusting portions are arranged dispersedly, a process of making an adjustment in assembling becomes very complicated. In addition, the adjusting portions are usually required to be covered with a cover. Then if pluralities of adjusting portions are arranged dispersedly, pluralities of covers are required to cover each adjusting portion. This makes not only a procedure of assembling or disassembling the chair but also a structure of the chair complicated.

[0007] In the present claimed invention some or all of the adjusting portions are gathered in a predetermined area in order to solve the above problems.

DISCLOSURE OF THE INVENTION

[0008] In order to solve the above-mentioned first problem, the present claimed invention intends to improve operationality for a chair having a plurality of operating portions to adjust a height of a back or a seat or to adjust a rocking motion, especially for a chair of multi-function by gathering some or all of the operating portions.

[0009] More specifically, the chair in accordance with the invention has a plurality of operating portions for adjusting a height of a back or a seat or for adjusting a rocking motion mechanically, and is characterized by that each of more than two operating portions as some or all of the operating portions is made to rotate around a predetermined shaft respectively and each shaft of the operating portions is arranged in a line as well.

[0010] With this arrangement, it is possible to gather the operating portions with a simple arrangement, for example, by mounting a plurality of operating portions on a single shaft and it is also possible to improve operationality especially for a chair of multi-function since operational style of each operating portions would be the same. Further, it is possible to provide a way of use that has not been existed before such that a plurality of operating portions can be operated at once with a single hand.

[0011] In order to improve operationality much more it is preferable that the above-described more than two operating portions are arranged below a side edge of the seat in a condition that each shaft extends back and forth. With this arrangement, it is possible for a user of the chair to touch the operating portions naturally if only the user extends his or her hand downward in sitting on the chair.

[0012] Further, with an arrangement wherein more than two operating portions are arranged together, it may happen that a user of the chair can not grasp which operating portion corresponds to a mechanism that he or she requires and that the user can not understand how to operate the operating portion. In order to avoid this inconvenience with a simple arrangement it is preferable that concavity and convexity is provided at a portion that can be touched on occasions when the operating portion is operated toward a predetermined direction on a surface of the above-described more than two operating portions. If it goes even a little further so that the concavity and the convexity are made to be distinctive in form, user-friendliness will be much improved.

[0013] In addition, in order to contribute to making a manufacturing process easy or to a low-price by promoting component sharing, it is preferable that the above-described more than two operating portions are of the same or generally the same shape.

[0014] As a concrete embodiment, it is represented that each of the above-described more than two operating portions are plate-shaped and can be kept to take a horizontal posture.

[0015] In addition, in order to solve the first problem, the chair in accordance with the invention has at least a back and a seat rocking function to rock a seat and a back in an interlocked condition, a back and a seat boundary portion adjusting function to move or transform the back and the seat boundary portion, a forwardly inclining angle adjusting function to adjust a forwardly inclining angle of the seat and a back and a seat up and down function to adjust a height of the back and the seat and is characterized by that the operating portions to operate each of the functions mechanically are gathered in a line in a predetermined area.

[0016] More concretely, the operating portions are arranged back and forth in a line below a side edge of the seat. With this arrangement, it is possible for a user of the chair to touch the operating portions naturally if only the user extends his or her hand downward in sitting on the chair.

[0017] In addition, an order of arranging the operating portions is determined based on an order of arranging members each of which produces a function of each operating portions so that it is easy for a user of the chair to understand and remember which operating portion corresponds to which function and to operate the operating portions easier as well. More concretely, the first priority is given to arranging the operating portion more front that corresponds to a function of a member locating lower. Next, in cases where the heights of the members are almost the same or difference of the height is obscure to determine, the operating portion which corresponds to a member locating more front is arranged more front.

[0018] Since a member that produces the back and the seat up and down function is a gas spring that is mounted on a leg and that locates the lowest, the operating portion to operate the gas spring is arranged at the most front position. Next, since a member that corresponds to the forward inclining angle adjusting function is mainly the seat, the operating portion to operate the forward inclining angle adjusting function is arranged next to the above-mentioned operating portion. Next, since a member that corresponds to the back and the seat boundary portion adjusting function locates at a boundary portion between the back and the seat, the operating portion to operate the back and the seat boundary portion adjusting function is arranged next to the former operating portion. And then since a member that corresponds to the back and the seat rocking function and the back reclining function is mainly the back, the operating portion to operate it is arranged at the rearmost.

[0019] In addition, the operating portions are made in the same or generally the same shape so as to produce a unitary impression to improve appearance and the operating portions are made to keep in a horizontal posture and can be in the same height when kept to take the horizontal posture. Further, concavity and convexity is provided at a position that can be touched on occasions when the operating portion is operated toward a predetermined direction on a surface of the adjusting portions so as to make it easy for the user of the chair to understand which direction to operate the operating portion.

[0020] In accordance with this embodiment, since the operating portions are gathered, a position of the operating portions can easily be recognized and operationality can be improved especially for a chair of multi-function. Further, it is possible to provide the chair with a new usage that has not been before such as a plurality of operating portions can be operated with a single hand simultaneously.

[0021] In order to solve the above-mentioned second problem, the chair in accordance with the invention has a plurality of working mechanisms such as an up and down mechanism to adjust a height of a seat and a back and a rocking mechanism or the like, and characterized by comprising an operating portion to be operated to work each mechanism, an operation receiving portion as a mechanism to work each mechanism directly and a link means that connects the operating portion and the operation receiving portion and further comprising adjusting portions that are arranged in the link means for adjusting a motion range of the operation receiving portion that works with operation of the operating portion wherein some or all of the two adjusting portions are gathered in a predetermined area.

[0022] In accordance with the arrangement, since a plurality of adjusting portions are gathered in a predetermined area, it is possible to adjust the adjusting portions at once, thereby to save time required to make an adjustment and to avoid a complicated process of assembling the chair.

[0023] In addition, in order to make a relationship of the operating portion to the adjusting portion clear, it is preferable to arrange the adjusting portions near the relevant operating portions.

[0024] In order to improve operationality for a user of the chair, it is preferable that at least the operating portions relevant to the above-mentioned adjusting portion are gathered. This arrangement makes it possible for the user to recognize a position of the operating portion at a glance.

[0025] As a concrete embodiment, it is preferable that the above-mentioned gathered adjusting portions are covered with a cover. Especially, in order to contribute reduction of a number of parts or a manufacturing cost or to simplify a process of assembling the chair, it is preferable that a boundary portion between the operating portion and the link means also is covered with a single cover.

[0026] A concrete preferable position to arrange the adjusting portion is represented by a position under the seat.

[0027] As one example of the link means, it is represented by the link means that uses a link wire.

BRIEF DESCRIPTION OF THE DRAWINGS

[0028]FIG. 1 is a general side view showing a chair in accordance with a first embodiment of the invention in a state of an ordinary use position and in a state wherein a lower portion of a backrest of the chair is made to project forward with the ordinary use position kept.

[0029]FIG. 2 is a general side view showing the chair in accordance with the embodiment in the most rearward inclined position.

[0030]FIG. 3 is a general side view showing the chair in accordance with the embodiment in a state wherein a back o the chair alone inclines rearward.

[0031]FIG. 4 is a general side view showing the chair in accordance with the embodiment in the most forwardly inclined position.

[0032]FIG. 5 is a partial perspective view showing an operating portion in accordance with the embodiment viewed from rear.

[0033]FIG. 6 is a partial plane view of the operating portion in accordance with the embodiment viewed from below.

[0034]FIG. 7 is a partial perspective view of the operating portion in accordance with the embodiment viewed from below.

[0035]FIG. 8 is a partial plane view of the operating portion in accordance with the embodiment viewed from front.

[0036]FIG. 9 is a partial plane view of the operating portion in accordance with the embodiment viewed from front.

[0037]FIG. 10 is a partial plane view of the operating portion in accordance with the embodiment viewed from below.

[0038]FIG. 11 is a cross-sectional view of a back reclining mechanism in accordance with the embodiment.

[0039]FIG. 12 is a cross-sectional view of the back reclining mechanism in accordance with the embodiment.

[0040]FIG. 13 is an explosive perspective view of the back reclining mechanism in accordance with the embodiment.

[0041]FIG. 14 is a general perspective view of a forward inclining angle adjusting mechanism in accordance with the embodiment.

[0042]FIG. 15 is a diagram showing a motion of the forward inclining angle adjust mechanism in accordance with the embodiment.

[0043]FIG. 16 is a general side view showing a chair in accordance with a second embodiment of the invention in a state of an ordinary use position and in a state wherein a lower portion of a backrest of the chair is made to project forward with the ordinary use position kept.

[0044]FIG. 17 is a general side view showing the chair in accordance with the embodiment in the most rearward inclined position.

[0045]FIG. 18 is a general side view showing the chair in accordance with the embodiment in a state wherein a back o the chair alone inclines rearward.

[0046]FIG. 19 is a general side view showing the chair in accordance with the embodiment in the most forwardly inclined position.

[0047]FIG. 20 is a partial perspective view showing an operating portion in accordance with the embodiment viewed from rear.

[0048]FIG. 21 is a partial plane view of the operating portion in accordance with the embodiment viewed from below.

[0049]FIG. 22 is a partial perspective view of the operating portion in accordance with the embodiment viewed from below.

[0050]FIG. 23 is a partial plane view of the operating portion in accordance with the embodiment viewed from front.

[0051]FIG. 24 is a partial plane view of the operating portion in accordance with the embodiment viewed from front.

[0052]FIG. 25 is a partial plane view of the operating portion in accordance with the embodiment viewed from below.

[0053]FIG. 26 is a cross-sectional view of a back reclining mechanism in accordance with the embodiment.

[0054]FIG. 27 is a cross-sectional view of the back reclining mechanism in accordance with the embodiment.

[0055]FIG. 28 is an explosive perspective view of the back reclining mechanism in accordance with the embodiment.

[0056]FIG. 29 is a general perspective view of a forward inclining angle adjust mechanism in accordance with the embodiment.

[0057]FIG. 30 is a diagram showing a motion of the forward inclining angle adjust mechanism in accordance with the embodiment.

[0058]FIG. 31 is a general side view of a whole chair in accordance with the embodiment.

[0059]FIG. 32 is a general bottom view of the operating portion of the chair in accordance with the embodiment.

[0060]FIG. 33 is a side view showing a third embodiment of the invention.

[0061]FIG. 34 is a front view showing the embodiment.

[0062]FIG. 35 is a general side view showing an inclining motion of the upper portion of the backrest alone and an inclining motion of the lower portion of the backrest.

[0063]FIG. 36 is a general side view showing a rocking motion in accordance with the embodiment.

[0064]FIG. 37 is a general side view showing an up and down motion of the seat and the back re accordance with the embodiment.

[0065]FIG. 38 is an explosive perspective view of a lock mechanism in accordance with the embodiment.

[0066]FIG. 39 is a plane view of a seat frame in accordance with the embodiment.

[0067]FIG. 40 is a plane view of an adjusting area in accordance with the embodiment viewed from bottom.

[0068]FIG. 41 is an explosive perspective view showing the adjusting area and a cover in accordance with the embodiment viewed from bottom.

[0069]FIG. 42 is a cross-sectional view showing the operating portion and the adjusting portion in accordance with the embodiment.

[0070]FIG. 43 is a cross-sectional view showing the operating portion and the adjusting portion in accordance with the embodiment.

[0071]FIG. 44 is a cross-sectional view showing the operating portion and the adjusting portion in accordance with the embodiment.

BEST MODES OF EMBODYING THE INVENTION

[0072] Embodiments of the invention will be described with reference to drawings.

[0073] <First Embodiment>

[0074] A first embodiment of the invention will be described in detail with reference to drawings thereof shown in FIG. 1 through FIG. 15.

[0075]FIG. 1 is a general side view of a chair X1 showing an embodiment of the present claimed invention. The chair X1 basically comprises a base leg X2, a support base X3 mounted on the base leg X2 and a seat X4 and a back X5 both of which are supported by the support base X3 and the chair X1 functionally has, as shown in FIG. 1 through FIG. 4, at least a back and a seat rocking function to interlock and rock the seat X4 and the back X5, a forward inclining angle adjusting function to adjust a forward inclining angle of the seat X4, a back reclining function to recline the back X5 alone, a back and a seat boundary portion adjusting function to move or transform a boundary portion between the back and the seat and a back and a seat up and down function to adjust a height of the seat X4 and the back X5.

[0076] More specifically, the support base X3 is lengthy and so arranged that a bottom end of the support base X3 is fittingly fixed over a top end of a support post X2 a that constitutes the base leg X2 and that a top end of the support base X3 extends at an angle to a forward direction.

[0077] The seat X4 is so arranged that a face X4 b to be seated is mounted on a frame-shaped seat frame X4 a.

[0078] The back X5 is so arranged that a covering member X5 b is mounted on a front face of a frame-shaped back support rod X5 a and has an appearance of upstanding continuously from a rear end of the seat X4. A backrest face of the back X5 is cushioned by making use of tension of the covering member X5 b.

[0079] Next, an arrangement to achieve the above-mentioned function will be explained.

[0080] The back and the seat rocking function is, as shown in FIG. 1 and FIG. 2, a function to engage and incline the seat X4 and the back X5 from an ordinal use position (FIG. 1) to the most forwardly inclined position (FIG. 2) and the seat X4 makes a motion rearward with taking a rearward inclined posture in accordance with a rearward inclined motion of the back X5 by making use of a four-side link mechanism XK1 lying between the support base X3, the seat X4 and the back X5.

[0081] The four-side link mechanism XK1 is, as shown in FIG. 1, so arranged that edges of four link members X6 a, X6 b, X6 c, X6 d are rotatably connected through shafts Xt1, Xt2, Xt3, Xt4 so that connected points form a trapezium in a side view wherein the support base X3 serves as a lower link member X6 a, the seat frame X4 a serves as an upper link member X6 b, the back support rod X5 (the lower frame X5 c that will be described later) serves as a rear link member X6 c and a front link member X6 d is arranged to connect front ends of the support base X3 and the seat frame X4 a.

[0082] In this embodiment, as shown in FIG. 1, FIG. 2, a rocking switch mechanism XK2 is provided in order to switch the back and the seat rocking function from an operable condition to an inoperable condition and conversely. The rocking switch mechanism XK2 is so made that one end of a first gas spring XGS1, which is a stretching member whose length can be switched from a free condition wherein the length can be stretched or contracted freely to a locked condition wherein the length is fixed, is rotatably fixed to the support base X3 at a position which is deviated from the shaft Xt3 connecting the front link member X6 d and that the other end of the first gas spring XGS1 is rotatably connected with the front link member X6 d at a position Xt6 which is deviated from the shaft Xt3 connecting the support base X3. When the first gas spring XGS1 is in the free condition, force is applied to the front link member X6 d to incline forward due to stretching force of the first gas spring XGS1 so as to urge the seat X4 and the back X5 to incline forward.

[0083] A switch button XB1 provided at the end of the first gas spring XGS1 is operated to switch the first gas spring XGS1 from the free condition to the locked condition and conversely and the switch button XB1 is connected to a first operating portion X14 that will be described later through a link wire XW1 and a condition of the first gas spring XGS1 can be switched from a condition wherein the seat X4 and the back X5 make a rocking motion to a condition wherein the seat X4 and the back X5 can be fixed at a desired angle and conversely by operating the first operating portion X14.

[0084] The forward inclining angle adjusting function is to switch a moving end of the seat X4 and the back X5 by the four-side link mechanism Xk1 to either one of an ordinal use position (FIG. 1) wherein the face X4 b is generally horizontal and a most forward inclined position (FIG. 4) wherein the face X4 b inclines forward a little by making use of a forward inclining angle adjusting mechanism XST1.

[0085] In this embodiment the forward inclining angle adjusting mechanism XST1, whose details are shown in FIG. 14 and FIG. 15, comprises a projecting portion X6 d 1 provided at an upper end of the front link member X6 d and a control member X41 provided at a position corresponding to the projecting portion X6 d 1.

[0086] The control member X41 is, as shown in FIG. 14, mounted on a shaft X42 provided to bridge over a rib X43 a of the seat frame X4 a and the control member X41 is in a disk shape of a certain thickness with a wedge portion X41 a projecting from an outer circumference of the disk shape. A guide cam X44 is mounted on an outer circumference of the rib X43 a of the seat frame X4 a at one end of the shaft X42 and an inclined cam X45 is provided to face to the guide cam X44 and a rotational direction of the control member X41 can be switched from an x direction to a y direction and conversely by an action of the inclined cam X45. The guide cam X44 is in a disk shape and a mountain portion X44 m protruded from a surface of the disk shape is provided so as to position at a valley portion X45 v of the inclined cam X45 that faces to the guide cam X44.

[0087] The inclined cam X45 is a slope one side of which facing to the guide cam X44 provided are the valley portion X45 v and a mountain portion X45 m and the other side of which is pushed toward an axial direction by a spring X46 so as to guide the mountain portion X44 m of the guide cam X44 to the valley portion X45 v of the inclined cam X45. The spring X46 is arranged between the inclined cam X45 and a side wall X43 b of the seat frame X4 a and is mounted on a rotational shaft XJ on which a lever X47 is mounted by winding around the rotational shaft XJ.

[0088] Next, for the chair X1 of the above arrangement a case wherein the seat X4 is moved from an ordinal use position (FIG. 1) to the most forward inclined position (FIG. 4) will be explained.

[0089] First, in a state of the ordinal use position (FIG. 1) a positional relationship between the front link member X6 d and the control member X41 and that of the guide cam X44 and the inclined cam X45 are shown in FIG. 15(a), namely, the wedge portion X41 a of the control member X41 is wedged between the projecting portion X6 d 1 of the front link member X6 d and a top plate of the seat frame X4 a. In this state the rotational shaft XJ is rotated to the y direction more than 90 degrees until the rotational shaft XJ reaches a rotation-controlled position, not shown in drawings, and then halted. Then the mountain position X45 m of the inclined cam x45 is rotated, as shown in FIG. 15(b), with making a sliding motion on the rotational shaft XJ to be separated from the guide cam X44 until the mountain portion X45 m reaches a position beyond the mountain portion X44 m of the guide cam X44. Since the inclined cam X45 is pushed toward the guide cam X44 by the spring X46, the mountain portion X44 m of the guide cam X44 is likely to rotate to the x direction after sliding down the mountain portion X45 m of the inclined cam X45, however the control member X41 and the guide cam X44 are in a condition of being unable to rotate because the wedge portion X41 a of the control member X41 is wedged by the projecting portion X6 d 1 of the front link member X6 d and a top plate X43 c of the seat frame X4 a.

[0090] With this condition kept, when a user of the chair X1 reclines the seat X4 and the back X5 rearward, the four-side link mechanism XK1 comprising the seat frame X4 a, the front link member X6 d, the lower flame X5 c and the support base X3 transforms so as to rotate the front link member X6 d around the shaft Xt3 to the x direction. With this motion, the projecting portion X6 d 1 of the front link member X6 d faces downward, which makes a space between the wedge portion X41 a and the top plate X43 c open, as shown in FIG. 15(c), and then the guide cam X44 rotates to the x direction that is reverse to a direction to which the inclined cam X45 is operated so that the mountain portion X44 m of the guide cam X44 locates at the valley portion X45 v of the inclined cam X45. In accordance with this motion, the inclined cam X45 rotates so as to return to the x direction and then halted in a state of being rotated at generally 90 degrees from the ordinal use position (FIG. 15(a)).

[0091] With this condition kept, when the seat X4 and the back X5 are returned to the original position, the four-side link mechanism XK1 transforms so that the front link member X6 d inclines forward and the seat frame X4 a on which the seat X4 is mounted inclines forward. In accordance with this motion, the back X5 rotates around the shaft Xt2 so as to incline forward (FIG. 15(d)).

[0092] In order to return the chair X1 from the forward inclining position (FIG. 15(d)) to the ordinal use position (a position wherein the front link member X6 d is upright), the rotational shaft XJ is rotated more than 90 degrees toward the x direction until it reaches the rotation controlled position, not shown in drawings and halted. In accordance with this motion, the mountain portion X45 m of the inclined cam X45 goes beyond the mountain portion X44 m of the guide cam X44 and then the mountain portion X44 m of the guide cam X45 rotates to the y direction like sliding down the mountain portion X45 m of the inclined cam X45 by a pushing force of the spring X4 f. Rotation of the rotational shaft XJ is halted when the wedge portion X41 a of the control member X41 contacts the projecting portion X6 d 1 of the front link member X6 d and the chair X1 is kept at the ordinal use position (the position at which the front link member X6 d is upright.

[0093] With this condition kept, when the seat X4 and the back X5 are inclined rearward, the four-side link mechanism XK1 transforms and the front link member X6 d rotates to the x direction around the shaft Xt3. In accordance with this motion, the projecting portion X6 d 1 of the front link member X6 d faces downward, as shown in FIG. 15(f), and a space between the wedge portion X41 a of the control member X41 and the top plate X43 c of the seat frame X4 a is made open so that the wedge portion X41 a of the control member X41 rotates and is wedged in the space.

[0094] With this condition kept, when the seat X4 and the back X5 is returned to the original position, the front link member X6 d transforms so as to return to the original position, which controls rotation of the front link member X6 d at the position where the wedge portion X41 a of the control member X41 is wedged. In accordance with this motion, the seat frame X4 a on which the seat X4 is mounted is set generally horizontal and is kept in the ordinal use position (the front link member X6 d is upright).

[0095] The back reclining function is a function to recline the back X5 alone and realized by the back reclining mechanism XK3. The back reclining mechanism XK3 is, as shown in FIG. 1 and FIG. 3, wherein the back support rod X5 a comprises the lower frame X5 c that locates under the seat frame X4 a and an upper frame X5 d that mainly corresponds to a backrest face and that is rotatably connected with the lower frame X5 c through a shaft Xt5 extending right and left horizontally, so arranged that the upper frame X5 d can be reclined to the lower frame X5 c between an upright posture (shown in FIG. 1) and the most reclined posture (shown in FIG. 3). The upper frame X5 d always receives force by a spring XS1 as an elastic member to a direction so as to take the upright posture and the spring XS1 is arranged in the lower frame X5 d with a direction to extend or contract coinciding with a longitudinal direction of the lower frame X5 c. The shaft Xt5 is set between the shaft Xt1 and the shaft Xt2 each of which constitutes the four-side link mechanism XK1 and a shaft of reclining the back X5 when the back X5 is reclined rearward by the use of the back reclining function and a shaft of reclining the back X5 when the back X5 is reclined rearward by the use of the back and the seat rocking function are arranged to be different. The spring XS1 is omitted to draw in FIG. 2 and FIG. 4.

[0096] Further in this embodiment a back reclining switch mechanism XK4 is provided to switch the back reclining function from an operable condition to an inoperable condition and conversely. The back reclining switch mechanism XK4 is, as shown in FIG. 11 through FIG. 13, to switch rotation of the upper frame X5 d to the lower frame X5 c from a condition wherein rotation is prohibited to a condition wherein rotation is allowed. More concretely, concave portions X5 d 1, X5 c 1 are provided at positions which overlap each other viewed from side in the upright posture and which deviate from the shaft Xt5 on the upper frame X5 d and the lower frame X5 c respectively, and the back reclining mechanism XK4 can be in an inoperable state when a pin X7 is inserted into the concave portions X5 d 1 and X5 c 1 and in an operable state when the pin X7 is drawn out of the holes X5 d 1 and X5 c 1.

[0097] The pin X7 is inserted into the hole X5 d 1 as a concave portion of the upper frame X5 d through the hole X5 c 1 as a concavity of the lower frame X5 c and a fringe portion X7 a is arranged at an opposite side of the pin X7 that is inserted into the holes X5 d 1 and X5 c 1 so that the pin X7 is kept out of at least the hole X5 d 1 of the upper frame X5 d when no external force is applied thereto as shown in FIG. 13 due to a coil spring XS2 arranged between the fringe portion X7 a and inner face of the upper frame X5 d.

[0098] A pin insertion hole X4 a 1 which opens to an outer face X4 a 2 of the seat frame X4 a and into which the pin X7 can be inserted is arranged on the seat frame X4 a that is arranged inner side to the upper frame X5 d and the lower frame X5 c, a pushing member X8 that travels to and fro inside the pin insertion hole X4 a 1 is mounted on the pin insertion hole X4 a 1 and the pin X7 is pushed outward by the pushing member X8 so as to be fittingly inserted into the hole X5 d 1 of the upper frame X5 d. The pushing member X8 is so set that can travel to and fro between a position wherein a face X8 a that pushes the pin X7 is flat to the outer face X4 a 2 (shown in FIG. 11) and a position wherein the face X8 a is recessed inward to the outer face X4 a 2 (shown in FIG. 12) and the motion of traveling to and fro is made by an operation of the first operating portion X14 through a motion transmission mechanism XD1 (shown in FIG. 6 and FIG. 13). The motion transmission mechanism XD1 comprises the link frame X9 whose one end is rotatably connected with the pushing member X8, a rotatable arm X10 whose rotatable end is connected with another end of the link frame X9 and that is rotatably supported by the seat frame X4 a and a link wire XW1 a whose one end is connected with the rotatable end of the rotatable arm X10 and that rotates the rotatable arm X10 by transmitting an operation of the first operating portion X14.

[0099] In case that the upper frame X5 d takes an upright posture to the lower frame X5 c (shown in FIG. 1), when the first operating portion X14 is operated to drive the pushing member X8 to a pushed position, the pin X7 is inserted into the holes X5 d 1 and X5 c 1, which prohibits the back X5 from rotating. When the first operating portion X14 is operated in a reverse manner, the pin X7 comes out of the hole X5 d 1 of the upper frame X5 d due to the coil spring XS2, which allows the back X5 to rotate.

[0100] In order to draw the pin X7 out of the hole X5 d 1 of the upper frame X5 d, a length of the pin X7 is set so that a face that is opposite to a face to be inserted locates inside of the outside face of the seat frame X4 a. More specifically, the pin X7 should be inserted into the pin insertion hole X4 a 1 in order to draw the pin X7 out of the hole X5 d 1 of the upper frame X5 d, wherein the pin insertion hole X4 a 1 overlaps the hole X5 c 1 of the lower frame X5 c in a side view, as shown in FIG. 1 and FIG. 2, only when the seat X4 and the back X5 are in the ordinal use position for the seat and back rocking function while the pin insertion hole X4 a 1 does not overlap the holes X5 d 1 and X5 c 1 in a side view when the seat X4 and the back X5 are in a state other than the ordinal use position. As a result, when the seat X4 and the back X5 are in the state other than the ordinal use position, the back reclining function can not be produced since the pin X7 can not be pulled out of the hole X5 d 1 because the opposite face to be inserted makes an abutment contact with the outer face X4 a 2 of the seat frame X4 a even though the user tries to draw the pin X7 out of the hole X5 d 1.

[0101] The first operating portion X14 serves as two functions such as a switch of the first gas spring XGS1 from the free condition to the locked condition and a switch of the pushing member X8 from a pressed position to an unpressed position, and in this embodiment when the first operating portion X14 is operated to a predetermined direction the first gas spring XGS1 is set in the free condition and the pushing member X8 is set at the pressed position, while the first operating portion X14 is set in the locked condition and the pushing member X8 is set at the unpressed position when the first operating portion X14 is operated to the opposite direction.

[0102] The back and the seat boundary moving function is a function, as shown in FIG. 1, which changes a inclined angle of the rear portion of the face X4 b and a projecting length of a lower portion of the backrest and makes use of an inclining body X12 that is arranged rear of the seat frame X4 a in an inclinable condition and a lumber support arm X13 integrally formed with a rear end of the inclining body X12.

[0103] The inclining body X12 is a pair of right and left frames extending back and forth and arranged below a rear end of a cushion or the like that constitutes the face X4 b, and the front end of the inclining body X12 is rotatably connected with the back support rod X5 (the lower frame X5 c) through the shaft Xt1. The inclining body X12 supports a rear portion X4 b 1 of the face X4 b in an inclinable manner between a lower position XL (shown by a solid line in FIG. 1) wherein the rear portion X4 b 1 is generally horizontal to the front portion X4 b 2 of the face X4 b and an upper position XU (shown by an imaginary line in FIG. 1) wherein the rear portion X4 b 1 of the face X4 b locates higher than a front portion thereof.

[0104] The lumbar support arm X13 is integrally formed with a rear end of the inclining body X12 to make a right angle in a side view and supports the covering member X5 b that forms a lower portion of the backrest from right and left thereof. The inclining body X12 projects forward in accordance as it makes a motion from the lower position XL to the upper position XU so as to project a lower portion of the backrest forward with increasing tension of the covering member X5 b. A bent portion X13 a that is bent to form an ark rearward is provided at a proximal end of the lumber support arm X13 provided is so as to improve a feeling to touch a lumber of a person who sits on this chair.

[0105] In this embodiment, a switch mechanism XK5 is provided to switch on/off of the back and the seat boundary moving function. The switch mechanism XK5 makes use of a second gas spring XGS2 as a stretching member whose length can be switched from a free condition wherein a length of the second gas spring XGS2 can be stretched or contracted freely to a locked condition wherein the length thereof is fixed by operating a switch button XB5 provided at an end of the second gas spring XGS2. One end of the second gas spring XGS2 is rotatably connected to a shaft Xt1 that connects the back support rod X5 a (more concretely, a lower frame X5 c) with the seat frame X4 a and another end thereof is rotatably connected at a position which is deviated from a shaft Xt5 connecting the back support rod X5 a. In this embodiment, when the second gas spring XGS2 is set in the free condition, force is applied to the inclining body X12 to incline it forward due to stretching force of the second gas spring XGS2. The switch button XB5 is connected to a second operating portion X15 which will be described later through a link wire XW2, and a state of the second gas spring XGS2 is switched by an operation of the second operating portion X15 from a state in which the back and the seat boundary portion can be moved or transformed to a state in which the back and the seat boundary portion is fixed to a desired shape.

[0106] A seat up and down function is a function to move the seat X4 and the back X5 up and down and is so arranged that a support post X2 a comprising the base leg X2 is made of a third gas spring XGS3 (shown in FIG. 7) and that a length of the support post X2 a is varied by making use of extension or contraction of the third gas spring XGS3 so as to move the seat X4 and the back X5 up and down. The third gas spring XGS3 is switched by a forth operating portion X17 that will be described later.

[0107] In this embodiment, the first, second, third and forth operating portions X14, X15, X16 and X17 are, as shown in FIG. 7, gathered in a line in this order from the rear to the front at the lower portion of the right side edge of the seat X4.

[0108] Each of the operating portions X14 through X17 is, as shown in FIG. 5 through FIG. 10, in a shape of a thin rectangular plate and has the same shape except for a proximal end thereof. Each of the proximal ends of the operating portions X14 through X17 is supported in a rotatable condition around a horizontal shaft that extends back and forth by an operating portion support frame X18 that is fixed to the seat frame X4 a and each of operational ends as distal ends thereof is arranged so as to protrude from a side of the chair X1 when the chair X1 is in a horizontal posture. Further each of the operational ends is arranged at the same height when the chair X1 is in the horizontal posture. Each shafts X19 of the operating portions X14 through X17 is arranged to be in the same line.

[0109] The first operating portion X14 switches, as described hereinbefore, on-off of the rocking function and fixes the seat X4 and the back X5 at a desired angle, while it switches on-off of the back reclining function as well. The first operating portion X14 is so arranged, as shown in FIG. 8, to make a toggle motion that is stabilized in a horizontal posture (solid line in FIG. 8) wherein the operational end projects outside of the chair X1 and a vertical posture (broken line in FIG. 8) wherein the operational end is rotated downward. More concretely, a point X14 a connecting the link wire XW1 with the first operating portion X14 is set at a position that is deviated from the shaft X19 of the first operating portion X14 and that bridges between an virtual line connecting a tube fixing point X18 a 1 arranged on the operation portion support frame X18 and the shaft X19 of the first operating portion X14 in accordance with a rotating motion of the first operating portion X14 between the horizontal posture and the vertical posture. The link wire XW1 is so arranged that force is always applied to pull the first operating portion X14 inward by an elastic member that is not shown in drawings so as to produce an effect of making a toggle motion. The rocking function is in a non-operational state in a horizontal posture and in an operational state in a vertical posture. The link wire XW1 is bifurcated halfway to form the link wire wires XW1 a and XW1 b, each of which is connected to the rotatable arm X10 or the first gas spring XGS1. A concavity and convexity XQ is partially provided on an upper face of the distal end of the first operating portion X14 so that the user is able to recognize the first operating portion X14 with his or her finger easily.

[0110] The second operating portion X15 is, as described before, to switch on-off of the back and the seat boundary portion moving function and to fix the back and the seat boundary portion in a desired form and is connected with the operating button of the second gas spring XGS2 through the link wire XW2. The second operating portion X15 is urged to take a horizontal posture by an elastic member such as a spring, not shown in drawings, in a natural state when no force is applied thereto and it makes a motion like a momentary switch. In the horizontal posture the second gas spring XGS2 is set in a fixed condition. Then when the user of the chair X1 operates the second operating portion X15 to rotate upward against the above-mentioned urging force as shown in FIG. 9, the second gas spring XGS2 is set in a free condition so that the inclining body X12 and the lumber support arm X13 can be inclined. A concavity and convexity XQ is provided on a lower face of the distal end of the second operating portion X15 partially so that the user can recognize the second operating portion X15 with his or her finger easily.

[0111] The third operating portion X16 shown in FIG. 10 is, as described hereinbefore, to switch an end of the seat X4 and the back X5 that are moved forward by the four-side link mechanism XK1 to either one of an ordinal use position wherein the face X4 b is generally horizontal or to the most forward inclined position wherein the face X4 b inclines forward a little. More concretely, the face X4 b can be set in the ordinal use position when the third operating portion X16 is operated to take the horizontal posture, while the face X4 b can be set in the most forwardly inclined position when the third operating portion X16 is operated to take the vertical posture.

[0112] The forth operating portion X17 is, as described hereinbefore, to adjust a height of the seat X4 and the back X5 and is connected to the operating button of the third gas spring XGS3 through a link wire XW4. The forth operating portion X17 is urged to take a horizontal posture by an elastic member such as a spring, not shown in drawings, in a natural state when no force is applied thereto and makes a motion like a momentary switch. In the horizontal posture the third gas spring XGS3 is set in a fixed condition. Then when the user of the chair X1 operates the forth operating portion X17 to rotate upward against the above-mentioned urging force, the third gas spring XGS3 is set in a free condition so that the seat X4 and the back X5 can be moved up and down. A concavity and convexity XQ is provided on a lower face of the distal end of the forth operating portion X17 so that the user can recognize the forth operating portion X17 with his or her finger easily.

[0113] This invention is not limited to the above-described embodiment and the operating portions are not limited to the above-described four. For example, in case a function is added to the face X4 b to allow a sliding motion back and forth, an operating portion may be arranged at a position whose height is the same as that of other existing operating portions, which will improve operationality. In this case, it is a matte of course that a relative distance between each operating portions changes due to the sliding motion depending on a position at which the operating portion is arranged.

[0114] Further, a shape of each operating portions may not be the same, a width of the operating portions may be varied and it is a matter of course that a distance between the operating portions is not limited to the same.

[0115] <Second Embodiment>

[0116] A second embodiment of the invention will be described in detail with reference to drawings thereof shown in FIG. 16 through FIG. 32.

[0117]FIG. 16 is a general side view of a chair Y1 showing an embodiment of the present claimed invention. The chair Y1 basically comprises a base leg Y2, a support base Y3 mounted on the base leg Y2 and a seat Y4 and a back Y5 both of which are supported by the support base Y3 and the chair Y1 functionally has, as shown in FIG. 16 through FIG. 19, at least a back and a seat rocking function to interlock and rock the seat Y4 and the back Y5, a forward inclining angle adjusting function to adjust a forward inclining angle of the seat Y4, a back reclining function to recline the back Y5 alone, a back and a seat boundary portion adjusting function to move or transform a boundary portion between the back and the seat and a back and a seat up and down function to adjust a height of the seat Y4 and the back Y5.

[0118] More specifically, the support base Y3 is lengthy and so arranged that a bottom end of the support base Y3 is fittingly fixed over a top end of a support post Y2 a that constitutes the base leg Y2 and that a top end of the support base Y3 extends at an angle to a forward direction.

[0119] The seat Y4 is so arranged that a face Y4 b to be seated is mounted on a frame-shaped seat frame Y4 a.

[0120] The back Y5 is so arranged that a covering member Y5 b is mounted on a front face of a frame-shaped back support rod Y5 a and has an appearance of upstanding continuously from a rear end of the seat Y4. A backrest face of the back Y5 is cushioned by making use of tension of the covering member Y5 b.

[0121] Next, an arrangement to achieve the above-mentioned function will be explained.

[0122] The back and the seat rocking function is, as shown in FIG. 16 and FIG. 17, a function to engage and incline the seat Y4 and the back Y5 from an ordinal use position (FIG. 16) to the most forwardly inclined position (FIG. 17) and the seat Y4 makes a motion rearward with taking a rearward inclined posture in accordance with a rearward inclined motion of the back Y5 by making use of a four-side link mechanism YK1 lying between the support base Y3, the seat Y4 and the back Y5.

[0123] The four-side link mechanism YK1 is, as shown in FIG. 16, so arranged that edges of four link members Y6 a, Y6 b, Y6 c, Y6 d are rotatably connected through shafts Yt1, Yt2, Yt3, Yt4 so that connected points form a trapezium in a side view wherein the support base Y3 serves as a lower link member Y6 a, the seat frame Y4 a serves as an upper link member Y6 b, the back support rod Y5 (the lower frame Y5 c that will be described later) serves as a rear link member Y6 c and a front link member Y6 d is arranged to connect front ends of the support base Y3 and the seat frame Y4 a.

[0124] In this embodiment, as shown in FIG. 16, FIG. 17, a rocking switch mechanism YK2 is provided in order to switch the back and the seat rocking function from an operable condition to an inoperable condition and conversely. The rocking switch mechanism YK2 is so made that one end of a first gas spring YGS1, which is a stretching member whose length can be switched from a free condition wherein the length can be stretched or contracted freely to a locked condition wherein the length is fixed, is rotatably fixed to the support base Y3 at a position which is deviated from the shaft Yt3 connecting the front link member Y6 d and that the other end of the first gas spring YGS1 is rotatably connected with the front link member Y6 d at a position Yt6 which is deviated from the shaft Yt3 connecting the support base Y3. When the first gas spring YGS1 is in the free condition, force is applied to the front link member Y6 d to incline forward due to stretching force of the first gas spring YGS1 so as to urge the seat Y4 and the back Y5 to incline forward.

[0125] A switch button YB1 provided at the end of the first gas spring YGS1 is operated to switch the first gas spring YGS1 from the free condition to the locked condition and conversely and the switch button YB1 is connected to a first operating portion Y14 that will be described later through a link wire YW1 and a condition of the first gas spring YGS1 can be switched from a condition wherein the seat Y4 and the back Y5 make a rocking motion to a condition wherein the seat Y4 and the back Y5 can be fixed at a desired angle and conversely by operating the first operating portion Y14.

[0126] The forward inclining angle adjusting function is to switch a moving end of the seat Y4 and the back Y5 by the four-side link mechanism Yk1 to either one of an ordinal use position (FIG. 16) wherein the face Y4 b is generally horizontal and a most forward inclined position (FIG. 19) wherein the face Y4 b inclines forward a little by making use of a forward inclining angle adjusting mechanism YST1.

[0127] In this embodiment the forward inclining angle adjusting mechanism YST1, whose details are shown in FIG. 29 and FIG. 30, comprises a projecting portion Y6 d 1 provided at an upper end of the front link member Y6 d and a control member Y41 provided at a position corresponding to the projecting portion Y6 d 1.

[0128] The control member Y41 is, as shown in FIG. 29, mounted on a shaft Y42 provided to bridge over a rib Y43 a of the seat frame Y4 a and the control member Y41 is in a disk shape of a certain thickness with a wedge portion Y41 a projecting from an outer circumference of the disk shape. A guide cam Y44 is mounted on an outer circumference of the rib Y43 a of the seat frame Y4 a at one end of the shaft Y42 and an inclined cam Y45 is provided to face to the guide cam Y44 and a rotational direction of the control member Y41 can be switched from an x direction to a y direction and conversely by an action of the inclined cam Y45. The guide cam Y44 is in a disk shape and a mountain portion Y44 m protruded from a surface of the disk shape is provided so as to position at a valley portion Y45 v of the inclined cam Y45 that faces to the guide cam Y44.

[0129] The inclined cam Y45 is a slope one side of which facing to the guide cam Y44 provided are the valley portion Y45 v and a mountain portion Y45 m and the other side of which is pushed toward an axial direction by a spring Y46 so as to guide the mountain portion Y44 m of the guide cam Y44 to the valley portion Y45 v of the inclined cam Y45. The spring Y46 is arranged between the inclined cam Y45 and a side wall Y43 b of the seat frame Y4 a and is mounted on a rotational shaft YJ on which a lever Y47 is mounted by winding around the rotational shaft YJ.

[0130] Next, for the chair Y1 of the above arrangement a case wherein the seat Y4 is moved from an ordinal use position (FIG. 16) to the most forward inclined position (FIG. 19) will be explained.

[0131] First, in a state of the ordinal use position (FIG. 16) a positional relationship between the front link member Y6 d and the control member Y41 and that of the guide cam Y44 and the inclined cam Y45 are shown in FIG. 30(a), namely, the wedge portion Y41 a of the control member Y41 is wedged between the projecting portion Y6 d 1 of the front link member Y6 d and a top plate of the seat frame Y4 a. In this state the rotational shaft YJ is rotated to the y direction more than 90 degrees until the rotational shaft YJ reaches a rotation-controlled position, not shown in drawings, and then halted. Then the mountain position Y45 m of the inclined cam Y45 is rotated, as shown in FIG. 30(b), with making a sliding motion on the rotational shaft YJ to be separated from the guide cam Y44 until the mountain portion Y45 m reaches a position beyond the mountain portion Y44 m of the guide cam Y44. Since the inclined cam Y45 is pushed toward the guide cam Y44 by the spring Y46, the mountain portion Y44 m of the guide cam Y44 is likely to rotate to the x direction after sliding down the mountain portion Y45 m of the inclined cam Y45, however the control member Y41 and the guide cam Y44 are in a condition of being unable to rotate because the wedge portion Y41 a of the control member Y41 is wedged by the projecting portion Y6 d 1 of the front link member Y6 d and a top plate Y43 c of the seat frame Y4 a.

[0132] With this condition kept, when a user of the chair Y1 reclines the seat Y4 and the back Y5 rearward, the four-side link mechanism YK1 comprising the seat frame Y4 a, the front link member Y6 d, the lower flame Y5 c and the support base Y3 transforms so as to rotate the front link member Y6 d around the shaft Yt3 to the x direction. With this motion, the projecting portion Y6 d 1 of the front link member Y6 d faces downward, which makes a space between the projecting portion Y6 d 1 and the top plate Y43 c open, as shown in FIG. 30(c), and then the guide cam Y44 rotates to the x direction that is reverse to a direction to which the inclined cam Y45 is operated so that the mountain portion Y44 m of the guide cam Y44 locates at the valley portion Y45 v of the inclined cam Y45. In accordance with this motion, the inclined cam Y45 rotates so as to return to the x direction and then halted in a state of being rotated at generally 90 degrees from the ordinal use position (FIG. 30(a)).

[0133] With this condition kept, when the seat Y4 and the back Y5 are returned to the original position, the four-side link mechanism YK1 transforms so that the front link member Y6 d inclines forward and the seat frame Y4 a on which the seat Y4 is mounted inclines forward. In accordance with this motion, the back Y5 rotates around the shaft Yt2 so as to incline forward (FIG. 30(d)).

[0134] In order to return the chair Y1 from the forward inclining position (FIG. 30(d)) to the ordinal use position (a position wherein the front link member Y6 d is upright), the rotational shaft YJ is rotated more than 90 degrees toward the x direction until it reaches the rotation controlled position, not shown in drawings and halted. In accordance with this motion, the mountain portion Y45 m of the inclined cam Y45 goes beyond the mountain portion Y44 m of the guide cam Y44 and then the mountain portion Y44 m of the guide cam Y45 rotates to the y direction like sliding down the mountain portion Y45 m of the inclined cam Y45 by a pushing force of the spring Y4 f. Rotation of the rotational shaft YJ is halted when the wedge portion Y41 a of the control member Y41 contacts the projecting portion Y6 d 1 of the front link member Y6 d and the chair Y1 is kept at the ordinal use position (the position at which the front link member Y6 d is upright.

[0135] With this condition kept, when the seat Y4 and the back Y5 are inclined rearward, the four-side link mechanism YK1 transforms and the front link member Y6 d rotates to the x direction around the shaft Yt3. In accordance with this motion, the projecting portion Y6 d 1 of the front link member Y6 d faces downward, as shown in FIG. 30(f), and a space between the wedge portion Y41 a of the control member Y41 and the top plate Y43 c of the seat frame Y4 a is made open so that the wedge portion Y41 a of the control member Y41 rotates and is wedged in the space.

[0136] With this condition kept, when the seat Y4 and the back Y5 is returned to the original position, the front link member Y6 d transforms so as to return to the original position, which controls rotation of the front link member Y6 d at the position where the wedge portion Y41 a of the control member Y41 is wedged. In accordance with this motion, the seat frame Y4 a on which the seat Y4 is mounted is set generally horizontal and is kept in the ordinal use position (the front link member Y6 d is upright)

[0137] The back reclining function is a function to recline the back Y5 alone and realized by the back reclining mechanism YK3. The back reclining mechanism YK3 is, as shown in FIG. 16 and FIG. 18, wherein the back support rod Y5 a comprises the lower frame Y5 c that locates under the seat frame Y4 a and an upper frame Y5 d that mainly corresponds to a backrest face and that is rotatably connected with the lower frame Y5 c through a shaft Yt5 extending right and left horizontally, so arranged that the upper frame Y5 d can be reclined to the lower frame Y5 c between an upright posture (shown in FIG. 16) and the most reclined posture (shown in FIG. 18). The upper frame Y5 d always receives force by a spring YS1 as an elastic member to a direction so as to take the upright posture and the spring YS1 is arranged in the lower frame Y5 d with a direction to extend or contract coinciding with a longitudinal direction of the lower frame Y5 c. The shaft Yt5 is set between the shaft Yt1 and the shaft Yt2 each of which constitutes the four-side link mechanism YK1 and a shaft of reclining the back Y5 when the back Y5 is reclined rearward by the use of the back reclining function and a shaft of reclining the back Y5 when the back Y5 is reclined rearward by the use of the back and the seat rocking function are arranged to be different. The spring YS1 is omitted to draw in FIG. 17 and FIG. 19.

[0138] Further in this embodiment a back reclining switch mechanism YK4 is provided to switch the back reclining function from an operable condition to an inoperable condition and conversely. The back reclining switch mechanism YK4 is, as shown in FIG. 26 through FIG. 28, to switch rotation of the upper frame Y5 d to the lower frame Y5 c from a condition wherein rotation is prohibited to a condition wherein rotation is allowed. More concretely, holes Y5 d 1, Y5 c 1 are provided at positions which overlap each other viewed from side in the upright posture and which deviate from the shaft Yt5 on the upper frame Y5 d and the lower frame Y5 c respectively, and the back reclining mechanism YK4 can be in an inoperable state when a pin Y7 is inserted into the holes Y5 d 1 and Y5 c 1 and in an operable state when the pin Y7 is drawn out of the holes Y5 d 1 and Y5 c 1.

[0139] The pin Y7 is inserted into the hole Y5 d 1 as a concavity of the upper frame Y5 d through the hole Y5 c 1 as a concavity of the lower frame Y5 c and a fringe portion Y7 a is arranged at an opposite side of the pin Y7 that is inserted into the holes Y5 d 1 and Y5 c 1 so that the pin Y7 is kept out of at least the hole Y5 d 1 of the upper frame Y5 d when no external force is applied thereto as shown in FIG. 28 due to a coil spring YS2 arranged between the fringe portion Y7 a and inner face of the upper frame Y5 d.

[0140] A pin insertion hole Y4 a 1 which opens to an outer face Y4 a 2 of the seat frame Y4 a and into which the pin Y7 can be inserted is arranged on the seat frame Y4 a that is arranged inner side to the upper frame Y5 d and the lower frame Y5 c, a pushing member X8 that travels to and fro inside the pin insertion hole X4 a 1 is mounted on the pin insertion hole X4 a 1 and the pin Y7 is pushed outward by the pushing member Y8 so as to be fittingly inserted into the hole Y5 d 1 of the upper frame Y5 d. The pushing member Y8 is so set that can travel to and fro between a position wherein a face Y8 a that pushes the pin Y7 is flat to the outer face Y4 a 2 (shown in FIG. 26) and a position wherein the face Y8 a is recessed inward to the outer face Y4 a 2 (shown in FIG. 27) and the motion of traveling to and fro is made by an operation of the first operating portion Y14 through a motion transmission mechanism YD1 (shown in FIG. 21 and FIG. 28). The motion transmission mechanism YD1 comprises the link frame Y9 whose one end is rotatably connected with the pushing member Y8, a rotatable arm Y10 whose rotatable end is connected with another end of the link frame Y9 and that is rotatably supported by the seat frame Y4 a and a link wire YW1 a whose one end is connected with the rotatable end of the rotatable arm Y10 and that rotates the rotatable arm Y10 by transmitting an operation of the first operating portion Y14.

[0141] In case that the upper frame Y5 d takes an upright posture to the lower frame Y5 c (shown in FIG. 16), when the first operating portion Y14 is operated to drive the pushing member Y8 to a pushed position, the pin Y7 is inserted into the holes Y5 d 1 and Y5 c 1, which prohibits the back Y5 from rotating. When the first operating portion Y14 is operated in a reverse manner, the pin Y7 comes out of the hole Y5 d 1 of the upper frame Y5 d due to the coil spring YS2, which allows the back Y5 to rotate.

[0142] In order to draw the pin Y7 out of the hole Y5 d 1 of the upper frame Y5 d, a length of the pin Y7 is set so that a face that is opposite to a face to be inserted locates inside of the outside face of the seat frame Y4 a. More specifically, the pin Y7 should be inserted into the pin insertion hole Y4 a 1 in order to draw the pin Y7 out of the hole Y5 d 1 of the upper frame Y5 d, wherein the pin insertion hole Y4 a 1 overlaps the hole Y5 c 1 of the lower frame Y5 c in a side view, as shown in FIG. 16 and FIG. 17, only when the seat Y4 and the back Y5 are in the ordinal use position for the seat and back rocking function while the pin insertion hole Y4 a 1 does not overlap the holes Y5 d 1 and Y5 c 1 in a side view when the seat Y4 and the back Y5 are in a state other than the ordinal use position. As a result, when the seat Y4 and the back Y5 are in the state other than the ordinal use position, the back reclining function can not be produced since the pin Y7 can not be pulled out of the hole Y5 d 1 because the opposite face to be inserted makes an abutment contact with the outer face Y4 a 2 of the seat frame Y4 a even though the user tries to draw the pin Y7 out of the hole Y5 d 1.

[0143] The first operating portion Y14 serves as two functions such as a switch of the first gas spring YGS1 from the free condition to the locked condition and a switch of the pushing member Y8 from a pressed position to an unpressed position, and in this embodiment when the first operating portion Y14 is operated to a predetermined direction the first gas spring YGS1 is set in the free condition and the pushing member Y8 is set at the pressed position, while the first operating portion Y14 is set in the locked condition and the pushing member Y8 is set at the unpressed position when the first operating portion Y14 is operated to the opposite direction.

[0144] The back and the seat boundary moving function is a function, as shown in FIG. 16, which changes a inclined angle of the rear portion of the face Y4 b and a projecting length of a lower portion of the backrest and makes use of an inclining body Y12 that is arranged rear of the seat frame Y4 a in an inclinable condition and a lumber support arm Y13 integrally formed with a rear end of the inclining body Y12.

[0145] The inclining body Y12 is a pair of right and left frames extending back and forth and arranged below a rear end of a cushion or the like that constitutes the face Y4 b, and the front end of the inclining body Y12 is rotatably connected with the back support rod Y5 (the lower frame Y5 c) through the shaft Yt1. The inclining body Y12 supports a rear portion Y4 b 1 of the face Y4 b in an inclinable manner between a lower position YL (shown by a solid line in FIG. 16) wherein the rear portion Y4 b 1 is generally horizontal to the front portion Y4 b 2 of the face Y4 b and an upper position YU (shown by an imaginary line in FIG. 16) wherein the rear portion Y4 b 1 of the face Y4 b locates higher than a front portion thereof.

[0146] The lumbar support arm Y13 is integrally formed with a rear end of the inclining body Y12 to make a right angle in a side view and supports the covering member Y5 b that forms a lower portion of the backrest from right and left thereof. The inclining body Y12 projects forward in accordance as it makes a motion from the lower position YL to the upper position YU so as to project a lower portion of the backrest forward with increasing tension of the covering member Y5 b. A bent portion Y13 a that is bent to form an ark rearward is provided at a proximal end of the lumber support arm Y13 provided is so as to improve a feeling to touch a lumber of a person who sits on this chair.

[0147] In this embodiment, a switch mechanism YK5 is provided to switch on/off of the back and the seat boundary moving function. The switch mechanism YK5 makes use of a second gas spring YGS2 as a stretching member whose length can be switched from a free condition wherein a length of the second gas spring YGS2 can be stretched or contracted freely to a locked condition wherein the length thereof is fixed by operating a switch button YB5 provided at an end of the second gas spring YGS2. One end of the second gas spring YGS2 is rotatably connected to a shaft Yt1 that connects the back support rod Y5 a (more concretely, a lower frame Y5 c) with the seat frame Y4 a and another end thereof is rotatably connected at a position which is deviated from a shaft Yt5 connecting the back support rod Y5 a. In this embodiment, when the second gas spring YGS2 is set in the free condition, force is applied to the inclining body Y12 to incline it forward due to stretching force of the second gas spring YGS2. The switch button YB5 is connected to a second operating portion Y15 which will be described later through a link wire YW2, and a state of the second gas spring YGS2 is switched by an operation of the second operating portion Y15 from a state in which the back and the seat boundary portion can be moved or transformed to a state in which the back and the seat boundary portion is fixed to a desired shape.

[0148] A seat up and down function is a function to move the seat Y4 and the back Y5 up and down and is so arranged that a support post Y2 a comprising the base leg Y2 is made of a third gas spring YGS3 (shown in FIG. 22) and that a length of the support post Y2 a is varied by making use of extension or contraction of the third gas spring YGS3 so as to move the seat Y4 and the back Y5 up and down. The third gas spring YGS3 is switched by a forth operating portion Y17 that will be described later.

[0149] In this embodiment, the first, second, third and forth operating portions Y14, Y15, Y16 and Y17 are, as shown in FIG. 22, gathered in a line in this order from the rear to the front at the lower portion of the right side edge of the seat Y4.

[0150] Each of the operating portions Y14 through Y17 is, as shown in FIG. 20 through FIG. 25, in a shape of a thin rectangular plate and has the same shape except for a proximal end thereof. Each of the proximal ends of the operating portions Y14 through Y17 is supported in a rotatable condition around a horizontal shaft that extends back and forth by an operating portion support frame Y18 that is fixed to the seat frame Y4 a and each of operational ends as distal ends thereof is arranged so as to protrude from a side of the chair Y1 when the chair Y1 is in a horizontal posture. Further each of the operational ends is arranged at the same height when the chair Y1 is in the horizontal posture. Each shafts Y19 of the operating portions Y14 through Y17 is arranged to be in the same line.

[0151] The first operating portion Y14 switches, as described hereinbefore, on-off of the rocking function and fixes the seat Y4 and the back Y5 at a desired angle, while it switches on-off of the back reclining function as well. The first operating portion Y14 is so arranged, as shown in FIG. 23, to make a toggle motion that is stabilized in a horizontal posture (solid line in FIG. 23) wherein the operational end projects outside of the chair Y1 and a vertical posture (broken line in FIG. 23) wherein the operational end is rotated downward. More concretely, a point Y14 a connecting the link wire YW1 with the first operating portion Y14 is set at a position that is deviated from the shaft Y19 of the first operating portion Y14 and that bridges between an virtual line connecting a tube fixing point Y18 a 1 arranged on the operation portion support frame Y18 and the shaft Y19 of the first operating portion Y14 in accordance with a rotating motion of the first operating portion Y14 between the horizontal posture and the vertical posture. The link wire YW1 is so arranged that force is always applied to pull the first operating portion Y14 inward by an elastic member that is not shown in drawings so as to produce an effect of making a toggle motion. The rocking function is in a non-operational state in a horizontal posture and in an operational state in a vertical posture. The link wire YW1 is bifurcated halfway to form the link wire wires YW1 a and YW1 b, each of which is connected to the rotatable arm Y10 or the first gas spring YGS1. A concavity and convexity YQ is partially provided on an upper face of the distal end of the first operating portion Y14 so that the user is able to recognize the first operating portion Y14 with his or her finger easily.

[0152] The second operating portion Y15 is, as described before, to switch on-off of the back and the seat boundary portion moving function and to fix the back and the seat boundary portion in a desired form and is connected with the operating button of the second gas spring YGS2 through the link wire YW2. The second operating portion Y15 is urged to take a horizontal posture by an elastic member such as a spring, not shown in drawings, in a natural state when no force is applied thereto and it makes a motion like a momentary switch. In the horizontal posture the second gas spring YGS2 is set in a fixed condition. Then when the user of the chair Y1 operates the second operating portion Y15 to rotate upward against the above-mentioned urging force as shown in FIG. 24, the second gas spring YGS2 is set in a free condition so that the inclining body Y12 and the lumber support arm Y13 can be inclined. A concavity and convexity YQ is provided on a lower face of the distal end of the second operating portion Y15 partially so that the user can recognize the second operating portion Y15 with his or her finger easily.

[0153] The third operating portion Y16 shown in FIG. 25 is, as described hereinbefore, to switch an end of the seat Y4 and the back Y5 that are moved forward by the four-side link mechanism YK1 to either one of an ordinal use position wherein the face Y4 b is generally horizontal or to the most forward inclined position wherein the face Y4 b inclines forward a little. More concretely, the face Y4 b can be set in the ordinal use position when the third operating portion Y16 is operated to take the horizontal posture, while the face Y4 b can be set in the most forwardly inclined position when the third operating portion Y16 is operated to take the vertical posture.

[0154] The forth operating portion Y17 is, as described hereinbefore, to adjust a height of the seat Y4 and the back Y5 and is connected to the operating button of the third gas spring YGS3 through a link wire YW4. The forth operating portion Y17 is urged to take a horizontal posture by an elastic member such as a spring, not shown in drawings, in a natural state when no force is applied thereto and makes a motion like a momentary switch. In the horizontal posture the third gas spring YGS3 is set in a fixed condition. Then when the user of the chair Y1 operates the forth operating portion Y17 to rotate upward against the above-mentioned urging force, the third gas spring YGS3 is set in a free condition so that the seat Y4 and the back Y5 can be moved up and down. A concavity and convexity YQ is provided on a lower face of the distal end of the forth operating portion Y17 so that the user can recognize the forth operating portion Y17 with his or her finger easily.

[0155] In accordance with this embodiment, since the operating portions Y14 through Y17 are gathered, a position of the operating portions Y14 through Y17 can easily be recognized and operationality can be improved especially for a multi-functional chair Y1. Further, it is possible to provide the chair Y1 with a new usage that has not been before such as a plurality of operating portions Y14 through Y17 can be operated with a single hand simultaneously. In addition, since the height of the operating portions Y14 through Y17 is set to be the same in a horizontal posture, it is possible to compare a position of the operating portion Y14 through Y17 that the user operates with other operating portions Y14 through Y17, which makes it possible for the user to recognize a status of the operating portion Y14 through Y17 that the user operates with ease.

[0156] This invention is not limited to the above-described embodiment and the operating portions are not limited to the above-described four. For example, in case a function is added to the face Y4 b to allow a sliding motion back and forth, an operating portion may be arranged at a position whose height is the same as that of other existing operating portions, which will improve operationality. In this case, it is a matte of course that a relative distance between each operating portions changes due to the sliding motion depending on a position at which the operating portion is arranged.

[0157] Further, a shape of each operating portions may not be the same, a width of the operating portions may be varied and it is a matter of course that a distance between the operating portions is not limited to the same.

[0158] <Third Embodiment>

[0159] A third embodiment of the invention will be described in detail with reference to drawings thereof shown in FIGS. 33 through 44. FIG. 33 and FIG. 34 are a side view and a front view of the chair 1 showing one embodiment of the invention respectively.

[0160] The chair 1 is, as shown in FIG. 35 through FIG. 37, so arranged that a back 5 and a seat 6 are supported by a base leg 2 and in order to make it possible to take a posture appropriately not only for sitting at a desk but also for rest or refreshment selectively the chair 1 is provided with an up and down mechanism P that adjusts a height of the back 5 and the seat 6, a rocking mechanism Q that rocks the back 5 and the seat 6 in an interlocked condition, a backrest upper portion inclining mechanism R that inclines an upper portion of the back 5 alone rearward for stretching and a backrest lower portion inclining mechanism S that is utilized for pressing a lumbar portion of a user of the chair 1.

[0161] More concretely, the base leg 2 is a rotating shaft 22 projecting upward from a center of leg blades 20 and so arranged to turn the seat 6 and the back 5 supported by the base leg 2 around the rotating shaft 22. The up and down mechanism P is so arranged that a gas spring 21 is incorporated into the rotating shaft 22 of the base leg 2 and locks the back 5 and the seat 6 at an optional height within a working range by working the gas spring 21 appropriately.

[0162] The back 5 comprises a backrest lower frame 50 and a backrest upper frame 55, and the frames 50 and 55 are rotatably mounted on a shaft 72 arranged inside of a link element 7 b.

[0163] The seat 6 can detachably be mounted on a seat frame 4.

[0164] The rocking mechanism Q mainly comprises a support base 3 mounted on the base leg 2, the seat frame 4 that supports the seat 6 and an inequilateral four-side link mechanism having the link elements 7 a and 7 b connecting the support base 3 with the seat frame 4 and further comprises a gas spring 31 that fixes the back 5 at an appropriate position.

[0165] The support base 3 is in a shape of V made of a rigid member such as die casted aluminum wherein a proximal end of the support base 3 is fixed to the rotating shaft and a distal end thereof projects upward at an angle. A torsion bar 70 that can store and discharge torsional elastic force through the rotational shaft 71 is arranged at an under face of the center of a hypotenuse of the support base 3.

[0166] The link element 7 a is plate-shaped, wherein one end of the link element 7 a is rotatably mounted on a front of the support base 3 through a shaft 30 and the other end thereof is rotatably mounted on a rear face of a front of the seat frame 4 and at least a shaft 60 is detachably mounted on a bearing 45 arranged on the seat frame 4.

[0167] One end of the link element 7 b is fixed to the torsion bar 70 arranged at the center of a hypotenuse of the support base 3 and other end thereof is rotatably connected with the rotational shaft 79 arranged at a rear side of the seat frame 4. The above-mentioned backrest lower frame 50 and the backrest upper frame 55 are integrally fixed to the link element 7 b with its rotation halted and can be rotated around the rotating shaft 71 together with the link element 7 b.

[0168] The gas spring 31 is arranged between the link element 7 a and the support base 3 and can lock whole of the four-side link mechanism by fixing the link element 7 a alternatively.

[0169] The backrest upper portion inclining mechanism R comprises a lock mechanism r and a spring member 73 and performs a function by allowing a rotation around the rotating shaft 72 of the backrest upper frame 55.

[0170] The lock mechanism r comprises, as shown in FIG. 38, a hole 77 provided on an upper part of the link element 7 b, a hole 551 provided on a bracket 550 arranged on the backrest upper frame 55 and a pin 76 that is usually arranged across the holes 551 and 77 and that selectively releases the backrest upper frame 55 from the link element 7 b by drawing out of the hole 551. A bracket 7 b 1 whose shape is the same as that of the bracket 550 is integrally formed with the link member 7 b provided inside the bracket 550 that locates inside of a lower end of the backrest upper frame 55 so that the pin 76 can be inserted into the hole 551 and the hole 77 that locates inside of the hole 551 with the brackets 550 and 7 b 1 overlap each other. In a state that the pin 76 is inserted into both of the holes 551 and 77, the link element 7 b and the backrest upper frame 55 are bound so as to move integrally. When the pin 76 is drawn out of the hole 551, the backrest upper frame 55 is released from the link member 7 b so that the backrest upper frame 55 alone can rotate around the shaft 72 independently.

[0171] In a state the pin 76 is inserted into the holes 77 and 550, a face 76 a of the pin 76 is pushed by a pushing member 9 and the pushing member 9 is connected with a motion transfer mechanism D1 for detaching the pin 76. The motion transfer mechanism D1 comprises a link frame 101 whose one end is rotatably connected to the pushing member 9 and an arm 102 that is rotatably supported by the seat frame 4 and a rotatable end of the arm 102 is rotatably connected to other end of the link frame 101.

[0172] The spring member 73 is to give elasticity to the backrest upper frame 55 when the backrest upper frame 55 reclines, in which a concavity portion 74 is arranged on a lower face of the upper end of the link member 7 b, one end of the spring member 73 is accommodated in the concavity portion 74 and fixed thereto and other end of the spring member 73 is mounted on the backrest upper frame 55 so as to push the backrest upper frame 55 toward a direction wherein the backrest upper frame 55 takes an upright posture with the spring member 73.

[0173] Further, the backrest lower portion inclining mechanism S makes use of the backrest lower frame 50 and is provided with a gas spring at a position where the lower frame 50 is pushed forward by making use of the rotational shaft 72 as a supporting point.

[0174] A first operating portion 43 a, a second operating portion 43 b and a third operating portion 43 c are gathered at the right front end of the seat frame 4, as shown in FIG. 39, in order to make active use of the above-mentioned mechanisms. The first operating portion 43 a is to move the seat 6 up and down, the second operating portion 43 b is to incline rearward the backrest lower frame 50 alone and the third operating portion 43 c is to engage and rock the seat 6, the backrest upper frame 55 and the backrest lower frame 50. If the third operating portion 43 c is operated downward while in a non-rocking state, the backrest upper frame 55 alone can be reclined.

[0175] A gas spring 21 to move the back 5 and the seat 6 up and down, a gas spring 54 to incline the backrest lower portion and a gas spring 31 to incline the backrest lower portion and the backrest upper portion are provided with a first operation receiving portion B1, a second operation receiving portion B2 and a third operation receiving portion B3 each of which is an operation receiving portion to directly operate the above-mentioned mechanism respectively. Each of the first operation receiving portion B1, the second operation receiving portion B2 and the third operation receiving portion B3 is a button and the gas springs 21, 54 and 31 are released from a locked state in accordance with a state of the button. In addition, the motion transfer mechanism D1 that is connected with the pin 76 that releases the backrest upper frame 55 from the link element 7 b also works as a forth operation receiving portion.

[0176] The operating portions 43 a, 43 b, 43 c and the operation receiving portions B1, B2, B3, D1 are connected by link means LW1, LW2, LW3 and LW4 respectively. A plane view of a portion K where the link means LW1, LW2, LW3 and LW4 and the operating portions 43 a, 43 b and 43 c are connected is shown in FIG. 40 and a perspective view thereof is shown in FIG. 41.

[0177] Each of the link means LW1, LW2, LW3, LW4 comprises a link wire LW11, LW21, LW31, LW41 and a tube LW12, LW22, LW32, LW42 as a pass defining means that defines a path of the link wire LW11, LW21, LW31, LW41 and into which the link wire LW11, LW21, LW31, LW41 is inserted.

[0178] On end of the link wire LW11 is connected with the first operating portion 43 a and other end thereof is connected with the first operation receiving portion B1. The link wire LW21 is connected with the second operating portion 43 b and the second operation receiving portion B2, the link wire LW31 is connected with the third operating portion 43 c and the third operation receiving portion B3 and the link wire LW41 is connected with the third operating portion 43 c and the forth operation receiving portion D1.

[0179] Both ends of the tubes LW12, LW22, LW32, LW42 are fixed to the seat frame 4.

[0180] In this embodiment, motion transfer members R1, R3 to transfer a motion of the first operating portion 43 a and the third operating portion 43 c into a horizontal motion of the first link means LW1 and the second link means LW3 are arranged in a middle of the first operating portion 43 a and the first link means LW1, and a middle of the third operating portion 43 c and the third link means LW3.

[0181] A principle of motion transfer by making use of the motion transfer member R1, R3 will be explained with reference to a case in which the motion transfer member R3 is combined with the third operating portion 43 c and the third link means LW3.

[0182] The motion transfer member R3 is rotatably supported by a bracket-shaped supporting portion 47 arranged in a side of the seat frame 4 and a portion CT2 that is deviated from a rotational center CT3 of the motion transfer member R3 is rotatably and slidably connected with a portion 43 c 1 that is deviated from a rotational center CT1 of the third operating portion 43 c.

[0183] More concretely, a shaft is protruded from the portion CT2 of the motion transfer member R3, the shaft is inserted into a groove arranged on the portion 43 c 1 of the third operating portion 43 c and the motion transfer member R3 and the third operating portion 43 c are rotatably and slidably connected between the portion CT2 and the portion 43 c 1. A relationship of the shaft and the groove may be reversed.

[0184] One end of the link wire LW3 constituting the third link means LW3 is connected with a wire link portion R31 set at a portion deviated from the rotational center CT3 and the portion CT2.

[0185] Further, the motion transfer member R3 is rotated at an angle more than the third operating portion 43 c and the wire link portion R31 is moved horizontally more than the rotational center CT1 of the third operating portion 43 c so as to transfer a motion of the third operating portion 43 c to a horizontal motion of the link wire LW3 effectively.

[0186] The wire link portion R31 is connected with one end of the link wire LW41 constituting the forth link means LW4 and works the same to a horizontal motion of the link wire LW4.

[0187] Explanation of the motion transfer member R1 will be omitted because it has the same arrangement as that of the motion transfer member R3.

[0188] The first link measure LW1, the second link measure LW3 and the forth link measure LW4 correspond to the up and down motion of the back 5 and the seat 6, the inclining motion of the backrest lower portion alone, the rocking motion and the inclining motion of the backrest upper portion alone in this order.

[0189] In order to make it easy for the user to recognize which operating portions 43 a through 43 c correspond to which mechanisms, for example, the operating portions 43 a through 43 c are arranged in this order from downward to upward of the chair 1 and the operating portions 43 a through 43 c are made in a shape of a plate whose upper face is provided with a guide showing a corresponding mechanism.

[0190] In this case, the third operating portion 43 c to rock all of the seat 6, the backrest upper frame 55 and the backrest lower frame 50 is made so as to switch from a horizontal state to a descending state and conversely and the first operating portion 43 a and the second operating portion 43 b are urged to take a horizontal state in a natural condition by a spring.

[0191] Next, a fundamental motion of the chair 1 having the above arrangement will be explained.

[0192] <Rocking Motion>

[0193] In a state that all of the operating portion 43 a through 43 c are horizontal (initial state), the gas spring 31 arranged under the seat 6 is in a free state. At this time the pin 76 is inserted into the hole 551 arranged on the backrest upper frame 55 as shown in FIG. 35 and the link element 7 b and the backrest upper frame 55 can incline rearward integrally around the rotational shaft 72. Then the four-side link mechanism transforms in accordance with a motion of the backrest upper frame 55 inclining rearward and the seat 6 inclines rearward to face downward so as to make a rocking motion as shown in FIG. 36. An imaginary line in FIG. 36 shows the state after the rocking motion is done.

[0194] In case that the third operating portion 43 c is operated downward after inclined rearward at a predetermined angle, the gas spring arranged under the seat 6 is kept in a fixed condition and maintains the angle inclined rearward.

[0195] <Backrest Upper Portion Alone Inclining Motion>

[0196] The link wire LW31 constituting the third link means LW3 is pushed inside, as shown by an imaginary line in FIG. 44, by pushing down the third operating portion 43 c from an initial state to downward, a state of the third operation receiving portion B3 changes in conjunction with the link wire LW31 and the gas spring 31 arranged under the seat 6 is locked so that a motion of the four-side link mechanism is fixed. Then the link wire LW41 as the forth link means LW4 is pushed inside, the arm 102 rotates, the link frame 101 moves by the motion transfer mechanism D1 as the forth operation receiving means shown in FIG. 38, the pushing member 9 moves away from the face 76 a of the pin 76 in conjunction with the above motion, the pin 76 is pulled out of the hole 551 provided on the backrest upper frame 55 by a work of the spring S1, and this makes it possible to recline the backrest upper frame 55 elastically with the seat 6 and the backrest lower frame 50 fixed. An imaginary line in FIG. 35 shows the motion.

[0197] <Backrest Lower Portion Alone Inclining Motion>

[0198] In case that the backrest lower frame 50 alone is moved rearward, the link wire LW21 constituting the second link means is pulled out as shown by an imaginary line in FIG. 43 by pulling up the corresponding second operating portion 43 b, a state of a button as the second operation receiving portion B2 changes in conjunction with the above motion and the gas spring 54 connected with the backrest lower frame 50 is released from a fixed state. This allows the backrest lower frame 50 to rotate. Then the link wire LW21 is pushed to return to the original position by returning the second operating portion 43 b to the original state at a predetermined position, the second operation receiving portion B2 returns to the original state in conjunction with the above motion, the gas spring 54 is fixed and then the backrest lower frame 50 is fixed to the state. An imaginary line in FIG. 36 shows the motion.

[0199] <Up and Down Motion>

[0200] In case that the first operating portion 43 a is non-operated, the gas spring 21 is locked and the back 5 and the seat 6 are fixed at a certain height. When the first operating portion 43 a if pulled up from this height, the link wire LW11 constituting the first link measure LW1 is pulled out as shown by an imaginary line in FIG. 42, a state of a button as the first operation receiving portion B1 changes in conjunction with the above motion, the gas spring 21 is released from a locked condition and then the back 5 and the seat 6 can be moved up and down within a predetermined range accompanied by a motion of an expansion and contraction. When the first operation portion 43 a is returned to a horizontal state, the link wire LW11 is pushed to return to the original position, the first operation receiving portion B1 returns to the original state in conjunction with the above motion, the gas spring 21 is locked and then the height of the back and the seat can be fixed. An imaginary line in FIG. 37 shows the motion.

[0201] The chair 1 of the embodiment is provided with adjusting portions AJ1, AJ2, AJ3, AJ4 for adjusting a motion range of the operation receiving means B1, B2, B3, D1 each of which operates the link means LW1, LW2, LW3, LW4 by an operation of the operating portions 43 a, 43 b, 43 c and all of the adjusting portions AJ1, AJ2, AJ3, AJ4 are gathered within a predetermined area.

[0202] The adjusting portions AJ1, AJ2, AJ3, AJ4 will be explained by taking the adjusting portion AJ1 as an example. The adjusting portion AJ1 is to change a path of the link wire LW11 that passes through the tube LW12 indirectly by changing a position where one end facing the first operating portion 43 a of the tube LW12 is fixed so as to change the path. Then an effective length of the link wire LW11 is changed so that the operation receiving portion B1 can make a motion within an appropriate range by operating the first operating portion 43 a. Concretely the first adjusting portion AJ1 comprises nuts LW122, LW123 that wedge either side of a mounting wall 461 dropping integrally from the under portion of the seat frame 4 and a helical portion LW121 that is formed one end of the tube LW12 and that helically connects with the nuts LW122, LW123.

[0203] Then helically proceeding or receding the nut LW122, LW123, can change the position where the end of the tube LS12 is fixed. Each of the second adjusting portion AJ2, the third adjusting portion AJ3 and the forth adjusting portion AJ4 has the same arrangement as that of the first adjusting portion AJ1.

[0204] In this embodiment, the mounting walls 461, 462, 463, 464 are arranged within an adjusting area 46 as the predetermined area in order to gather all of the adjusting portions AJ1, AJ2, AJ3, AJ4. The adjusting area 46 is arranged under the seat frame 4 and adjacent to the inner side of the operating portions 43 a, 43 b, 43 c.

[0205] Each of the mounting walls 461, 462, 463, 464 makes a right angle with the corresponding link wire LW11, LW21, LW31, LW41 respectively and a cut out portion 461 a, 462 a, 463 d, 464 a is formed on each of the corresponding mounting walls 461, 462, 463, 464. Counter sunk portions 461 b, 462 b, 463 b, 464 b into which the nuts LW122, LW222, LW323, LW423 fit respectively are arranged, as shown in FIG. 41, on one side of the walls near the cut out portions 461 a, 462 a, 463 a, 464 a.

[0206] A way to adjust the operation receiving portions B1, B2, B3, D1 with the adjusting portions AJ1, AJ2, AJ3, Aj4 will be explained.

[0207] More specifically, for a case that the operation receiving portion B1, B2, B3, D1 is operated by the operating portion 43 a, 43 b, 43 c linked through the link means LW1, LW2, LW3, LW4, if the link wire LW11, LW21, LW31, LW41 is pushed too deep or withdrawn too much, the operation receiving portion B1, B2, B3 D1 might not work even through the operating portion 43 a, 43 b, 43 c is operated. Then in order to make the operation receiving portion B1, B2, B3 D1 work appropriately by operating the operating portion 43 a, 43 b, 43 c, a path of the tube is changed by the use of the adjusting portion AJ1, AJ2, AJ3, AJ4 so as to adjust a withdrawn length of the link wire LW11, LW21, LW31, LW41.

[0208] More concrete procedure of adjusting the length will be explained with reference to an example of the first operating portion 43 a, the first link means LW1, the first adjusting portion AJ1 and the mounting wall 461. First, pass the link wire LW11 constituting the first link means LW1 through the cut out portion 461 a.

[0209] Next, proceed or recede the two nuts LW122, LW123 constituting the first adjusting portion AJ1 helically to the helical portion LW121 of the tube LW12 so as to adjust the position of the nuts LW122, LW123 so that the first operation receiving portion B1 works appropriately by the operation of the first operating portion 43 a and to wedge the mounting wall 461 between the nuts LW122, LW123. A process of adjusting a set of the second operating portion 43 b, the second link means LW2, the second adjusting portion AJ2 and the mounting wall 462, a set of the third operating portion 43 c, the third link means LW3, the forth link means LW4, the third adjusting portion AJ3, the forth adjusting portion AJ4, the mounting wall 463 and the mounting wall 464 is the same.

[0210] As shown in FIG. 41, the adjusting area 46 and a boundary portion K between the operating portion 43 a, 43 b, 43 c and the link means LW1, LW2, LW3, LW4 can be covered with a cover C.

[0211] The cover C is provided with a window C1 a to pass through the first operating portion 43 a, a window C1 b to pass through the second operating portion 43 b and a window C1 c to pass through the third operating portion 43 c and claws C21, C22, C23, C24 that are means to fix the cover C to a resin seat frame cover CZ that covers the seat frame 4 and the under face of the seat frame are provided at a plurality of portions on a peripheral wall of the cover C.

[0212] The windows C1 a, C1 b, C1 c make a general right angle with extended directions of the operating portions 43 a, 43 b, 43 c respectively, widths of the windows C1 a, C1 b, C1 c generally equal to widths of the first operating portion 43 a, the second operating portion 43 b, the third operating portion 43 c respectively and heights thereof generally conform to operating ranges of the operating portions that correspond to the windows C1 a, C1 b, C1 c.

[0213] The claws C21, C22, C23 are geared with the seat frame 4 or the seat frame cover CZ in order to fix the cover C to the seat frame 4.

[0214] Since the chair 1 in accordance with the embodiment has an arrangement in which the adjusting portions AJ1, AJ2, AJ3, AJ4 are gathered in the adjusting area 46, the adjusting portions AJ1, AJ2, AJ3, AJ4 can be taken out from the chair 1 in order to make an adjustment, which makes it possible to make an adjustment at once, thereby to prevent a procedure of assembling the chair 1 from being complicated.

[0215] In addition, since the operating portions 43 a, 43 b, 43 c are arranged to gather near the adjusting portions AJ1, AJ2, AJ3, AJ4, a relationship between the operating portions 43 a, 43 b, 43 c and the adjusting portion AJ1, AJ2, AJ3, AJ4 becomes clear for a user of the chair 1, thereby to improve operationality.

[0216] Further, since a cover C is provided to cover both of the adjusting portions AJ1, AJ2, AJ3, AJ4 and the boundary portion between the adjusting portions AJ1, AJ2, AJ3, AJ4 and the operating portions 43 a, 43 b, 43 c, it becomes possible to protect those portions from external force and to improve appearance as well with a piece of the cover C, thereby to reduce a number of components and a manufacturing cost and also to simplify a procedure of assembling.

[0217] This invention is not limited to the above-described embodiment. For example, the operating portion may be arranged apart from the adjusting portion and the operating portions may not be gathered. The cover may cover the adjusting portion alone or may be omitted. A position of the adjusting portion may be, for example, above an armrest apart from under the seat. A link having rigidity may be used as the link means apart from the link wire and the tube.

POSSIBLE APPLICATIONS IN INDUSTRY

[0218] As mentioned above, in accordance with the invention of claim 1, it is possible to gather the operating portions with a simple arrangement, for example, by mounting a plurality of operating portions on a single shaft and it is also possible to improve operationality especially for a chair of multi-function since operational style of each operating portions would be the same. Further, it is possible to provide a way of use that has not been existed before such that a plurality of operating portions can be operated at once with a single hand.

[0219] In addition, if the above-described more than two operating portions are arranged below a side edge of the seat in a condition that each shaft extends back and forth, it is possible for a user of the chair to touch the operating portions naturally if only the user extends his or her hand downward in sitting on the chair.

[0220] Especially, if the above-described more than two operating portions are plate-shaped and can be kept to take a horizontal posture, user-friendliness or operationality can be much improved.

[0221] Further, with an arrangement wherein more than two operating portions are arranged together, it may happen that a user of the chair can not grasp which operating portion corresponds to a function that he or she requires and that the user can not understand how to operate the operating portion. However, if concavity and convexity is provided at a portion that can be touched on occasions when the operating portion is operated toward a predetermined direction on a surface of the above-described more than two operating portions, it is possible to avoid the above-mentioned inconvenience with a simple arrangement.

[0222] If the above-described more than two operating portions are of the same or generally the same shape, it can contribute to making a manufacturing process easy or to a low-price by promoting component sharing.

[0223] In addition, in accordance with the invention of claim 6, since the operating portions are gathered, a position of the operating portions can easily be recognized and operationality can be improved especially for a chair of multi-function. Further, it is possible to provide the chair with a new usage that has not been before such as a plurality of operating portions can be operated with a single hand simultaneously.

[0224] Further, if the above-mentioned more than two operating portions are arranged back and forth in a line below a side edge of the seat, it is possible for a user of the chair to touch the operating portions naturally if only the user extends his or her hand downward in sitting on the chair, thereby to improve user-friendliness or operationality.

[0225] In addition, if an order of arranging the operating portions is determined based on an order of arranging members each of which produces a function of each operating portions, it is easy for a user of the chair to understand and remember which operating portion corresponds to which function and to operate the operating portions easier as well.

[0226] Similarly, in order to improve usability or operationality much more, it is preferable that the above-mentioned more than two operating portions are arranged at the same height, they are made to have the same or generally the same shape, they are made to be plate-shaped and kept in a horizontal posture or they are made to have an arrangement wherein its proximal end is rotatably supported by the seat and its distal end can make an up and down movement.

[0227] Further, with an arrangement wherein more than two operating portions are arranged together, it may happen that a user of the chair can not grasp which operating portion corresponds to a function that he or she requires and that the user can not understand how to operate the operating portion. However, it is possible to avoid this inconvenience with a simple arrangement if concavity and convexity is provided at a portion that can be touched on occasions when the operating portion is operated toward a predetermined direction on a surface of the above-described more than two operating portions.

[0228] Further, in accordance with the invention of claim 12, since the chair has a plurality of working mechanisms such as an up and down mechanism to adjust a height of a seat and a back and a rocking mechanism or the like and comprises an operating portion to be operated to work each mechanism, an operation receiving portion as a mechanism to work each mechanism directly and a link means that connects the operating portion and the operation receiving portion and further comprising adjusting portions that are arranged in the link means for adjusting a motion range of the operation receiving portion that works with operation of the operating portion wherein some or all of the two adjusting portions are gathered in a predetermined area, it is possible to adjust the adjusting portions at once and to avoid a complicated process of assembling the chair. As a result of this, the chair can contribute a user and a manufacturer of the chair. 

1. A chair having a plurality of operating portions to adjust a height of a back or a seat or to adjust a rocking motion mechanically, and characterized by that each of more than two operating portions as some or all of the operating portions is made to rotate around a predetermined shaft respectively and each shaft of the operating portions is arranged in a line as well.
 2. The chair described in claim 1, wherein the above-described more than two operating portions are arranged below a side edge of the seat in a condition that each shaft extends back and forth.
 3. The chair described in claim 1 or 2, wherein concavity and convexity is provided at a portion that can be touched on occasions when the operating portion is operated toward a predetermined direction on a surface of the above-described more than two operating portions.
 4. The chair described in claim 1, 2 or 3, wherein the above-described more than two operating portions are of the same or generally the same shape.
 5. The chair described in claim 1, 2, 3 or 4, wherein each of the above-described more than two operating portions are plate-shaped and can be kept to take a horizontal posture.
 6. A chair having a plurality of operating portions to adjust a height of a back or a seat or to adjust a rocking motion mechanically, and characterized by that more than two operating portions as some or all of the operating portions are gathered in a line in a predetermined area.
 7. A chair having a plurality of operating portions to adjust a height of a back or a seat or to adjust a rocking motion, and characterized by that more than two operating portions as some or all of the operating portions are arranged back and forth in a line below a side edge of the seat.
 8. The chair described in claim 6 or 7, wherein an order of arranging the above-mentioned more than two operating portions is determined based on an order of arranging members that produce a function to be an object of each operating portions.
 9. The chair described in claim 6, 7 or 8, wherein the above-described more than two operating portions are of the same or generally the same shape.
 10. The chair described in claim 6, 7, 8 or 9, wherein concavity and convexity is provided at a position that can be touched on occasions when the operating portion is operated toward a predetermined direction on a surface of the above-described more than two adjusting portions.
 11. The chair described in claim 6, 7, 8, 9 or 10, wherein each of the above-described more than two operating portions can be kept to take a horizontal posture and are in the same height when kept to take the horizontal posture.
 12. A chair having a plurality of working mechanisms such as an up and down mechanism to adjust a height of a seat and a back, a rocking mechanism or the like, and characterized by comprising an operating portion to be operated to work each mechanism, an operation receiving portion as a mechanism to work each mechanism directly and a link means that connects the operating portion with the operation receiving portion and further comprising adjusting portions that are arranged in the link means in order to adjust a motion range of the operation receiving portion that works with operation of the operating portion wherein more than two adjusting portions as some or all of the adjusting portions are gathered in a predetermined area.
 13. The chair described in claim 12, and characterized by that the adjusting portions are arranged near the relevant operating portions.
 14. The chair described in claim 12 or 13, and characterized by that the operating portions are gathered in a predetermined area.
 15. The chair described in claim 12, and characterized by further comprising a cover that covers the adjusting portions arranged together.
 16. The chair described in claim 15, and characterized by that the cover also covers a boundary portion between the operating portion and the adjusting portion.
 17. The chair described in claim 12, 13, 14, 15 or 16, and characterized by that the adjusting portion is arranged under the seat.
 18. The chair described in claim 12, 13, 14, 15, 16 or 17, and characterized by that a link wire is used as the link means. 